Polymerization promoter



United States Patent 3,177,189 POLYMERIZA'HON PROMOTER Robert Fuhrmann,Dover, and Fred W. Kali, Clifton, N.J., assi@ors to Allied Chemical Corporation,New York, N.Y., a corporation of New York No Drawing; 'FiledJan. 27, 1961, Ser. No. 85,190 (Ilaims. (Cl. 260- 933) olefins has been disclosed by Ziegler and Montecatini in Australian patent application 40,207, dated August 5,

- 1958. Those compounds possess the general formula i in which A represents an element selected from the Group =erization and in'some cases the stereospecificity of the catalyst byseveralunits percent, e.g. to a maximum of 88.3 percent for tetrabutyl ammonium iodide.

We have found that 2-oxo-morpholinium halides of the formula tic hydrocarbon radicals containing from one to twenty carbon atoms, and X" is a halide'selected from the group consisting of iodide, bromide, chloride and fluoride, not only greatly increases the polymerization rate of alpha-olefins when usedfin conjunction .with the'catalytic complex, alpha-TiCl .A1(alkyl) but also produces polymers which are at least 94-95 percent stereoregular. The eiiicacy of this catalyst isextremely surprising, since one would expect the carbonyl group of the oxo-morpholinum halide to be reduced by the trialkly aluminum cocatalyst. Such a redox reaction would be expected to render the catalyst useless.

The production of polymers with such high stereo regularity presents an important advantage in that one does not need to refine the polymer in order to remove its amorphous contents. In an unrefined polymer of low stereoregularity, the amorphous components tend to pass 'into solution and thereby increase .the viscosity of the mixture. This produces a sticky end product which is difiicult to handle and must therefore be refined.

Preferred are those 2-oxo-rnonpholinium halides in 3,177,189 Patented Apr. 6}, 1965 which the N-substituted groups are either aryl, aralkyl, branched or straight chain hydrocarbon radicals containing from 1 to 10 carbon atoms per radical.

Examples of 2-oxo-rnorpholinum halides which are suitable as promoters for the polymerization of alphaolefins to stereospecific polymer are set forth in the following list of compounds, wherein the halide may be a member selected .from the group consisting of iodide, bromide, chloride, and fluoride:

N-ethyl,N-cyclohexyl-2-oxo-morpholiniurn halide N-butyLN-cyclohexyl-2-oxo-morpholinium halide N-ethyl,N-phenyl-2-oxo-monpholinium halide N-butyl,N-pheny1-2-oxo-morpholinium halide N-ethyl,N-benzyl-Zmxo-morpholinum halide N-butyl,N-benzyl-2-oxo-morpholinium halide I N,N-diethyl-Z-oxo-morpholinum halide N-ethyl,N-isobutyl-2-oxo-morpholinium halide N-neopentyl,N-ethyl-2 oxo-morpholinium halide The titanium chloride used as one ingredient of our catalyst is preferably alpha-Ticl i.e., the violet crystalline form of titanium chloride obtainable by reduction of titanium tetrachloride with hydrogen; by reduction of titanium tetrachloride with titanium metal powder, by reduc tion of titanium tetrachloride with an aluminum trialkyl followedby heating the reaction product under nitrogen, e.g., to 300; etc. However, other forms of TiCl such as beta, gamma and delta, are useful for the rapid polymerization of alpha-olefins to highly stereoregular polymers. Preferred alkyl aluminum compounds to be used as ingredients of our catalyst are aluminum trialkyls having -'1-4 carbon atoms in the alkyl groups such as trimethyl aluminum, triethyl aluminum and triisobutyl aluminum. The stereoregularity of propylene polymers produced with either triethyl or triisobutyl aluminum cocatalysts is of the order of 95 percent, whereas in the presence of triwherein R and R are like or different aliphatic or aroma- Organometallic compounds in which the metal is other than aluminum, can also'be used in this :process. Both dialkyl zinc and dialkyl cadmium may be used, and they will provide effective control on the molecular weight of the polymer, i.e., they will lower it.

These catalyticingredlien'ts are contacted generally in an inert reaction medium such as pentane, hexane, heptane and isooctane. The trialkyl aluminum compound is soluble in such solvents, and TiCl can be suspended as a fine powder in the solvent. The trialkyl aluminum concentration can range from 5 to millimoles per liter. Within this range increasing trialkyl aluminum concentration results in increasing rates of polymerization accompanied by the formation of polymers of decreasing molecular weight. The stereoregularity of the polymers, however, remains uniformly high throughout. It is only at exceptionally high trialkyl aluminum concentrations beyond the upper limits of this range that the stereoregularity of' the polymers begins to decrease. A trialkyl aluminum concentration of 20 to 60 millimoles per liter is especially preferred.

In contrast thereto, the TiCl concentration is not critical. Concentrations of this compound can rangefrom 0.1 gram per liter upward to such concentrations that the reaction becomes difiicult to control because of exothermic effects.

Referring now to the proportions of the 2-oxo-morpholiniumhalide promoter to. be used in making up our catalyst, we have found that at least under the generally used polymerization conditions there is a preferred molecular ratio of 2-oxo-morpholinium halide to be-used" range from 60:1 to 521.. The ratio of trialkyl aluminum to promoter may be as high as 100:1. Polymerization will also occur at ratios as low as 1:1, but for ratios lower than this, no polymerization of alpha-olefins occurs.-

The catalyst described hereinabove is capable of polymerizing alpha-olefins of the general formula /R Y CH2=CH-GH The following examples describe specific embodiments of our modified catalyst and of a process .of making it and of polymerizing alpha-olefins therewith, and are rep-.

resentative of the best mode contemplated by us of carrying out our invention. Nevertheless, theexamples are .to be understood as illustrative only;and the invention is not to be understood as. confined to all detailsofthe examples.

Except as otherwise indicated in the. examplesthe pro- ,cedure used was as follows:

A three-necked flask equipped with a mechanical stirrer,

gas inlet tube, thermometer and refluxcondenser was thoroughly dried. The flask was then flushed with 99.9 percent purepropylene-gas which was devoid of oxygen or any oxides. ml. of -n-heptane was introducedand became saturated with propylene. N,N-diethyl-2-oxo-morpholiniium chloride was next introduced, followed by the alpha-Ticl jin 50 ml. of the liquid medium, and then by the triethyl aluminum. The reaction temperature was maintained at,

70 C. by a water bath and the reaction time was counted from the introduction of the trialkyl aluminum to stop-. ping the flow of propylene throughlthe reactionmedium containing the catalyst and promoter.

For determining reaction rates and composition ofv the polymer at the end of the desired reaction period,

the contents of the flask were mixed withlSOO ml. of methanol. The insoluble polymer was filtered from the liquid and'refined. To this end the polymer was simmered with grams of a 5-10 percent solutionof concentrated (33 percent) aqueous -HCl in methanol for every one gram of the polymer. The polymer was filtered.

off and simmered three timesin about 20grams methanol for every one gram of polymer for to 60 minutes. After each of these treatments the solid polymer was filtered off. The polymer recovered from the final simmering step was dried in a current of air at room tempera-.

ture.

The stereoregular polypropylene fraction of the refined, dried polymer was separated by first extracting with boiling ethyl ether and then with boiling n-heptane. The residue of these extractions is the .stereoregular form. Theseextractions were carried out in a Walker-Bailey extractor operating over a period of 24 hours for each extraction.

Continuing the flow of propylene, 350

Atmospheric pressures. were maintained these experiments.

I Al/Ti/Di- Polyrn. g.,alphaethy1-2oxo- Rate, Percent Example T101; morph. g./g./hr. Stereo- M Temp, Time, regularity Ratio 0. Hrs.

While the above describes'the preferred embodiments of the invention, ,it will be-:understood that departures can be made therefrom within :the scope of the specification and claims.

We claim: 1 p v 1. A titanium trichloride/trialkyl aluminum-compound catalyst for alpha-olefin polymerization modified by addition thereto of a promoter consisting essentially of 2- oxo-morpholinium halide of the formula HzU CH V 1 JG; on, 0 0/ V wherein R and R are hydrocarbon radicals eachcontaining from'one to twenty carbon atoms, X is a halide selected from the group consisting of iodide, bromide, chloride, and fluoride, and wherein the, molecular proportion of said 2-oxo-morpholinium halideper molecular proportion of trialkyl aluminum is in the range from about 1: 100 to about 1:1.

2. A catalyst as defined in claim 1, wherein the titanium trichloride is alpha-titanium trichloride, and there is included as an alkyl compound, a trialkyl aluminum having 1-4 carbon atoms in eachQof the alkyl groups.

3. A catalyst as defined inclaim 2, wherein the trialkyl aluminum is triethyl aluminum.:

4. A catalyst as defined in claim 1, wherein the 2-0x0- morpholinium halide is.N,N-diethyl-2-oxo-n1orpholinium chloride. 1

5. A process of modifying a titanium trichloride/trialkyl aluminum compound catalyst to promote said catalyst for the production of stereoregular polymers from alpha-olefins, which comprises .admixingwith said catalyst a promoter consisting essentially of 2-oxo-morpholinium halide as defined in claim 1, the molecular proportion of said morpholinium halide per molecular proportion of trialkyl aluminum being in the range from about 1:100 to 'about lzl. I I

6. In a process of'polymerizing alpha-olefins to solid polymers using as a catalyst a combination of alphatitanium trichloride and a trialkyl aluminum compound, the'improvement which comprises admixing-with said catalyst a promoter consisting essentially, of 2-oxo-morpholiniumhalide as defined in claim 1, the molecular proportion of said morpholinium halide per molecular proportion of trialkyl'aluminum being in the range between about 1:5 and about 1:60.

7. The improvement as defined in claim 6 -wherein the alpha-olefin possesses the general formula R (Eugen-C wherein R and Rare members selected from the group Reaction rates are expressed in the examples in terms of (grams polymer/ gram Ticl in catalyst) /hour.

conlsisting of hydrogen, alkyl, cycloalkyl, aralkyl and ary 8. The improvement as defined in claim 6, wherein the alpha-olefin is propylene.

9. The improvement as defined .in claim 8, wherein the titanium trichloride is alpha-titanium trichloride, and the trialkyl aluminum compound possesseszl-4 carbon atoms in each alkyl group; the. molecularproportion of 6 e3 2-oxo-morpl1olinium halide per molecular proportion of 2,905,645 9/59 Anderson et al. 252-429 trialkyl aluminum is in the range between about 1:5 and 2,925,392 2/60 Seelbach et a1. 252429 1:60. 2,932,633 4/60 Juveland et a1. 260-949 10. The improvement as defined in claim 8, wherein the 2-ox0-m0rph0linium halide is N,N-diethy1-2-0X0- 5 F REIGN PATENTS h morpholimum c londe 526,101 5/55 Italy References Cited by the Examiner UNITED STATES PATENTS JOSEPH L. SCHOFER, Primary Examiner. 2,879,263 3/59 Anderson (it al. 260-949 10 j GREENV/ALD, Exam/linen 2,886,560 5/59 Weber 26094.9 

6. IN A PROCESS OF POLYMERIZING ALPHA-OLEFINS TO SOLID POLYMERS USING AS A CATALYST A COMBINATION OF ALPHATITANIUM TRICHLORIDE AND A TRIALKYL ALUMINUM COMPOUND, THE IMPROVEMENT WHICH COMPRISES ADMIXING WITH SAID CATALYST A PROMOTER CONSISTING ESSENTIALLY OF 2-OXO-MORPHOLINIUM HALIDE AS DEFINED IN CLAIM 1, THE MOLECULAR PROPORTION OF SAID MORPHOLINIUM HALIDE PER MOLECULAR PROPORTION OF TRIALKYL ALUMINUM BEING IN THE RANGE BETWEEN ABOUT 1:5 AND ABOUT 1:60. 